diff --git a/spec/outputs/file_spec.rb b/spec/outputs/file_spec.rb
index de0ab60..429c768 100644
--- a/spec/outputs/file_spec.rb
+++ b/spec/outputs/file_spec.rb
@@ -1,6 +1,7 @@
 # encoding: UTF-8
 require "logstash/devutils/rspec/spec_helper"
 require "logstash/outputs/file"
+require "logstash/codecs/line"
 require "logstash/event"
 require "logstash/json"
 require "stud/temporary"